Owner`s manual

FUSE:
This is the A.C.’s (Alternating Current) main fuse and provides protection from outside A .C. fluctuations as well as power
tube failure damage. Should the fuse blow, replace it with the same rating in a Slo-Blo type package. The domestic U.S. version
requires a 2 amp Slo-Blo fuse. A power tube short or failure is often the cause of a blown fuse...Follow
the cold start procedure mentioned in the POWER & STANDBY switch section and watch the
power tubes as you flip the STANDBY switch to the ON position. If a power tube is going bad or
is arcing you will see it! Flip the STANDBY switch to Standby immediately and replace the faulty
power tube and the fuse if necessary. If you see nothing abnormal as you lift the STANDBY
switch, it is possible that a power tube shorted temporarily and blew the fuse. If this is the case it may work again normally. To be extra
safe, you might want to replace just the adjacent tube or all power tubes in the “shotgun” troubleshooting tradition and save the
replaced set as spares. Spare fuses are a must for the fabled cord bag along with your spare tubes. Always carry both for they could
be worth their weight in gold someday.
Now that we’ve reviewed the 20/20’S Front Panel controls and found its simple layout to be easily digested, let’s move aft for a review
of the Rear Panel connections.
INPUTS A / B:
Located to the far left (when facing the unit from the rear) you’ll find two 1/4” insulated jacks. These are the inputs
for preamps and/or effects, depending on how you wire your system. You may drive the 20/20 with your preamp directly or choose
to come from the last effect in a chain and drive the power amp this way.
Either way is fine and up to your preference.
SPEAKERS:
These six jacks deliver the 20/20’S incredible tone to your favorite speaker cabinets. One eight Ohm and two four
Ohm jacks per channel are provided. Use one eight Ohm cabinet in the eight Ohm jack of each channel and two eight Ohm cabinets
into the two four Ohm jacks per channel. Use one four Ohm cabinet into one
four Ohm jack (each channel). Use one sixteen Ohm cabinet into the eight
Ohm jack (each channel). Two sixteen Ohm cabinets connected with a “Y”
cable works even better in the eight Ohm jack, once again this would be the
same for each channel.
Don’t forget: Duplicate the proper load for both channels: Turn its VOLUME Control to zero and its PRESENCE Control all the
way up. It’s also best not to send signal to the unused channel input.
PAGE 4
REAR PANEL:
8 OHMS
INPUT
B
A
4 OHMS 4 OHMS
SLAVE
B
A
8 OHMS
INPUT
4 OHMS 4 OHMS
SLAVE
B
A
B
A
FRONT PANEL CONTROLS: (Continued)
8 OHMS
INPUT
B
A
4 OHMS 4 OHMS
SLAVE
B
A
POWER
2A SB
FUSE
1A SB
SB
STANDBY
VOLUME
VOLUME